John young



(No Model.) t

J. YOUNG.

DASH EOTr EoE STEAM ENGINES.

. Patentd'-MaE. 9, 1886.

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ilNTTnn STATES PATENT Ottica.

JOHN YOUNG, OF NEWARK, NEW JERSEY.

DASH-POT FOR STEAM-ENGINES.

SPECIFICATION forming part of Letters Patent. 210.337.644, dated March9. '1886.

Application tiled December 21, 1885. Serial No. 186,293. (No model.)

.To all whom it may] concern:

Be it known that I, JOHN YOUNG, of Newark, Essex county, in the State ofNew Jersey, have invented a certain new and useful Improvement inDash-Pots for Steam Engines, of which the following is a specification.

I employ the term dash-pot77 to indicate the device-one for eachsteam-valve-whieh, when the valveisliberated, iirst acts to prompt- ]yeffect the closing and then to gently arrest the closing motion. I havedevised important improvements in thc construction. I make the dash-potannular, with the central portion Y over this central post.

the highest. Thefgipiston is guided on a smoothly-turned central post. Iprovide means l'or maintaining a`nearl y perfect vacuu m The annularchamber which surrounds the base of this post imprisons a quantity ofair, which resists the descent of the piston near the bottom and gentlyarrests the mot-ion. Iattach particular importance to provisions forallowing the air to escape downward from this chamber into anotherconveniently arranged below. On the rising ofthe piston with the openingof the valve, air is drawn upward again from the said lower chamber. Iprovide for taking the air downward from and delivering it to thechamber at two or more different levels and for adj ustably contractingthe effective area of these openings. The interior ofthe cylinder whichincloses the base of the piston is formed` with an offset, as is commonin this class of devices, allowing the air to flow out andthe piston todescend freely during the first part ofthe closing movement. Below thisoffset I bore'conically, so that as the' piston descends the air belowis at iirst imprisoned only partly, the tightness ofthe tit increasingas the piston descends. I provide means for introducing oil to thevacuum-chamber on the top of the central post, and for entirelyexcluding the air after each supply. The reservoir of oil thus providedinsures efficient lubrication. It will now be understood that at eachopening of the valve the piston, in the form of an inverted cap withcylindrical sides and a sufficiently broad bottom rim, is drawn upforcibly, making a vacuum under the high central portier., which remainsunbroken during the whole movement. Under the rim of the piston novacuum is formed at any period, because the air can enter with tolerablefreedom through the contracted passages from belov.T during ali portionof the rising movement, and as soon as the piston rises well into theconical portion of the bore and at all the later stages ofthe openingmovement the air is admitted freely from above. On the liberation ofthevalve my piston descends rapidly and is arrested gently. the drawingin and forcing out of the air through the contracted passages in thelower portion are smothered by its communication with the chamber belowinstead of into the open air. This makes the operation silent. Iinterpose leather in the vacuui'i'i-chamber in the center, and also inthe annular arrestingchamber, to soften the concussion, when from anycause the descent is not otherwise sufficiently arrested. I'allow thepiston to turn around freely on the central post. motes itswearinguniformly. A circular groove in the bottom of the annulararrestingchamber puts all portions in free communication with the oneormore contracted passages through which this chamber communicates withthe chamber below. The central post is hollow, and, by the aid of avalve mounted in the upper portion, delivers downward the contents ot'the central or Vacuum chamber at each descent ofthe piston. All theparts are easy of access for examination or repairs.

rIhe accompanying drawings form a part of this specification, andrepresent what I consider the best means of carrying out the invention.

Figure l is a vertical central section. Fig. 2 is a plan view. Fig. 3 isa corresponding View ofthe central portion with the piston relnoved.Fig. 4 is a horizontal section on the line x :v in Fig. l.

Similar letters of reference indicate corresponding parts in all thefigures where they occur. n

It will be understood that in my dash-pot, as in others, the piston islifted and liberated at variable periods, according to the point atwhich the steam is to be cnt off. 0n being liberated, it descendsrapidly, and at the termination of the downward movement is arrestedgently.

The sounds produced byl This pro-g lOO A designates the fixed portion ofthe appa` ratus. I will use additional marks, as A', when necessary toindicate special parts thereof.

A is a portion of the bed-plate of the engine. (Not represented.)

A2 is the base-plate, faced upon A, and held firmly down by suitablebolts inserted through lugs Ai. (See Fig. 2.) In its upper face is acirculargroove, a. A passage, m, leads down from this groove into achamber below.

A4 is what I term the post,7 a hollow cylindrical casting, formed in onewith A2, finished on its exterior, and grooved horizontally, asindicated by a. The whole is inclosed in a deep rimor hollow cylinder, AA, The lower portion, A5, is bored cylindrically for alittle distance upfrom the base, and tapering above. At ai is an offset, the interiorspace being considerably enlarged at this level. Above this offset therim AU extends upward further. The annular space between the post A4 andthe rim A5 AG is open at the top. A passage, fn, (see Fie'. 1,) isdrilled or otherwise produced in the position represented. It iscontrolled by an adjustable screwplug, N. The passage m is controlled byan adj ustable screw`pl ug. M.

B is the piston, certain portions being designated when necessary byadditional marks, as B B.

B is a cylindrically-bored portion fitting closely around the post A4,and free to move up and down and also to turn around thereon.

B2 is a stout bottom flange, and B1 the top, provided with ascrew-threaded neck, spherically bored.

C is a spherically-bored cap, having an octagonal exterior and ascrew-threaded interior, with a. properlyshaped aperture in the top toallow vibration to the operating-rod D, which is formed with a sphericallower end, D', and is properly connected at the upper end to theValve-operating mechanism. (Not represented.)

Eis a removable casing tapped into the top of the postA4, and forming aseat for an automatic valve, G, mounted within and held up gently to itsseat by a coiled spring, H, which latter abuts on the removable plug E',fitted in the base oi'E. There is avertical winged space around thevalve H. The upper end of the casing E is hexagonal. T.Vhen the rod D isdisconnected and the piston is lifted off, the casing E may beconvenientlyinserted and removed by applying an ordinary wrench.

I is an annular piece ot' soleleather secured by screws z on the topofthe post A4.

J is an annular piece of sole-leather secured by screwsj on the lowerface ofthe flange B2.

A screw-plug, P, serves to tightly close an orifice through which asmall quantity of oil should be introduced at short intervals.

Operation: At each opening of the steamvalve (not represented) thepiston is forcibly raised, thereby forming a cylindrical chamber overthe post A4, and an annularchamber under the flange B". In the topchamber is, at each elevation of the piston, a nearly perfect vacuum.The annular chamber under the flange B2 is always filled with air, theair being drawn in at the commencement through the apertures m and n,and at a later stage in the rising motion of the piston flowing freelyin from above, as will be obvious. The pressure of the externalatmosphere over the top chamber contributes with gravity to induce aprompt descent ofthe piston so soon as itis liberated. As the pistondescends, it con1- lnences to imprison the air under it. In the lastpart of the descending motion, after the lower edge ofthe piston hastraversed the tapering part of A5 and reached the cylindrical portion,the only escape for the air below is through the passages m and n. Theplugs M and N should be set so as to open these passages justsuiiiciently to allow the valve to close rapidly, but without.-concussion. Sound is produced by the rapid movement ofthe air throughthe passages m and n; but my arrangement insures that this is soeit'ectually conlined to the bottom chamber, a, that it is inapprcciablein the engine-room.

The leathers I and J perform an important function. It will often occurin practice that in the effort to adjust the screw-plugs M and N toallow the valve to shut very promptly the piston will not be quiteenough cushioned, and will strike on the bottom. insure that suchcontact will never be metal with met-ai, but always through theinterposition of these leathers. So soon as the concussion attractsattention, one or both thescrews M and N should be set in alittle, so asto retard the escape of air from under the pistou a little more.Concussion will thus loe removed.

I have shown four horizontal grooves, a, extending around the post'A4.There may be one or a series ofsuch grooves, one above another. Theirfunction is to form pockets, which have the effect to retard the ow ofair or oil through the joint, which is necessarily easy between the postA4 and the interior of the piston B. One alone may serve.

The vacuum-chamber over the center post is marked rv, the annularcushioningchamber under the flange B" is marked y, and the bottomchamber,f which receives the blasts of air through the orilices m and nat each descent and suppresses the sound, is marked z.

The groove a2,4 turned orotherwise produced in the upper face of A2,insures a free communication from all parts of the cushioningchamber tothe orifice m, even when the piston is quite down.

Further modilications may be iliade. The

proportions of the parts may be changed. The post A* may be more or lesshigh. l can vary the form ot' the controlling means M and N, whichadjust the area ofthe passages l'or the flow of the air from the annularchamber under the piston into the bottom chamber at each descent.

Parts of the appara-tus maybe used without the whole. I can dispensewith the upperpor- The leathers ICO IIO

tion of the rim A5. The eect of this portion of the apparatus is mainlyto protect theinterior parts from injury from the introduction of hardsubstances or other cause when the piston is raised.

I claim as my invention- 1. The post A4, made hollow, as shown, incombination with the valve G, mounted in the interior near the top, aspring, H, and piston B, adapted to form a tight vacuum-chamber over thepost, and an annular cushioningchamber or dash-pot around the bottom, asherein specified.

2. The post A4, piston B, and cylinder A6 A, tapered below the offset,and arranged for jointoperation as herein specified.

3. The piston B, cap C, and rod D, with its spherical end D', incombination with each other and with the post A*,valve G, 'and cylinderA5, arranged for joint operation as herein speciiied.

4. In adash-pot, the bottom chamber, z, and

passage m between the same and the cushioning-chamber 1 in combinationwith the piston B and operating means D, arranged to serve as hereinspecified.

5. The duplicate passages m n and controlling means M N, leading' fromdifferentleVe-ls in the dash-pot, communicating with the same bottomchamber,and arranged to serve as here- 3o in specified.

6. In a dash-pot, in combination with the rim A5, piston B, operatingmeans D, hollow post A, valve G, and spring H, the removable casingE,adapted to serve as herein speci- 35 fied.

In testimony whereof Ihavehereunto set my hand, at New York city, NewYork, this 19th day of December, 1885, in the presence of twosubscribing witnesses. e

JOHN YOUNG.VV

Witnesses:

WILLIAM S. WATTS, Crus. H. SoNN.

